QAY300 adopts 7-axle chassis, 5-axle steering, 4-axle drive, elliptic section jib, and single-cylinder no-rope automatic stretch and retract, having strong lifting performance. Through the application of the fieldbus technique, the computer integration control technique makes the product failure diagnosis highly intelligent, and makes the control highly automatic. The mature application of limit load in accordance with the power makes the machine energy efficient, low noisy, environmental friendly, and safe. The variable-rigidity air and hydraulic suspension technique makes the machine comfortable to drive and have good stability and longitudinal trafficability.The additional equipment of the machine includes super-lift device, luffing jib, and fixed lengthening jib, which increase the lifting performance and working scope in an unimaginable proportion. The working radius and lifting height are respectively up to 86m and 116m.